1. Technical Field
The present invention relates to a polybutylene naphthalate-based resin composition used as an insulating material and an electric wire using the polybutylene naphthalate-based resin composition. The electric wire of the present invention is an insulated wire including a single-layered electric wire and multi layered-electric wire. Also, the electric wire of the present invention includes a cable.
2. Description of Related Art
Conventionally, as an electric insulating material, an insulating material normally made of polyvinyl chloride resin (PVC) has been used. Such an insulating material made of PVC is excellent in an aspect of having a high practical characteristic at a low cost. However, due to generation of smoke including hazardous gas by combustion, materials excluding PVC have been requested in recent years.
In a transport field of automobiles and trains, etc, in order to save energy, electric wires are requested to be made light and thin, as a vehicle body is made to be lighter and space-saving in wiring is promoted.
When a conventional PVC material is applied to such a lightening/thinning of the electric wire, there is a problem that requests characteristics such as flame retardant property and abrasion resistance can not be achieved. Further, in recent years, in order to prevent a great social confusion that occurs in skyscraper fire and fire of cables that extend all around underground mall and subway, etc, flame resistance and suppression of smoke emission at the time of combustion are desired. In this point also, the requests can not be satisfied by the PVC material.
Meanwhile, polyester resin, being an engineering plastic polymer, above all, polybutylene terephthalate (PBT) is a crystalline polymer, and is used in a fuel tube for an automobile and a liquid crystal glass polishing device member, and a semiconductor-related member, etc, by utilizing characteristics such as heat resistance, mechanical strength, gas barrier property, chemical resistance, abrasion resistance, low elution property, and moldability (for example, see patent documents 1 to 3).
These engineering plastic have the aforementioned characteristics, and therefore there is a prospect that the lightening/thinning of the electric wires is achieved.
Patent Documents
    (Patent document 1) Japanese Patent Laid Open Publication No. 2005-281465    (Patent document 2) Japanese Patent Laid Open Publication No. 2006-152122    (Patent document 3) Japanese Patent Laid Open Publication No. 2007-45952    (Patent document 4) Japanese Patent Laid Open Publication No. 2006-111655    (Patent document 5) Japanese Patent Laid Open Publication No. 2006-111873    (Patent document 6) Japanese Patent Laid Open Publication No. 2005-213441    (Patent document 7) Japanese Patent Laid Open Publication No. 2004-193117    (Patent document 8) Japanese Patent Laid Open Publication No. 2002-358837    (Patent document 9) Japanese Patent Laid Open Publication No. 2001-316533    (Patent document 10) Japanese Patent Laid Open Publication No. 11-1581